Lactic acid bacteria growth requirements

After World War II, analytical methods for amino acids were improved and new methods were iatroduced. The first was microbial assay usiag lactic acid bacteria which require all of the regular amino acids for growth. Manometric determiaation (by use of a Warburg manometer) of CO2 Hberated by the... 

Vitamins and Minerals. Milk is a rich source of vitamins and other organic substances that stimulate microbial growth. Niacin, biotin, and pantothenic acid are required for growth by lactic streptococci (Reiter and Oram 1962). Thus the presence of an ample quantity of B-complex vitamins makes milk an excellent growth medium for these and other lactic acid bacteria. Milk is also a good source of orotic acid, a metabolic precursor of the pyrimidines required for nucleic acid synthesis. Fermentation can either increase or decrease the vitamin content of milk products (Deeth and Tamime 1981 Reddy et al. 1976). The folic acid and vitamin Bi2 content of cultured milk depends on the species and strain of culture used and the incubation conditions (Rao et al. 1984). When mixed cultures are used, excretion of B-complex vita-... 

Enterobacter aerogenes, B. subtilis, P. fluorescens, and Serratia marces-cens produce acetoin by decarboxylation of a-acetolactate. However, yeasts and E. coli form acetoin from the acetaldehyde-TPP complex and free acetaldehyde (Rodopulo et al 1976). These organisms do not decarboxylate a-acetolactate, but use it to produce valine and pantothenic acid. In lactic acid bacteria, a-acetolactate is not used for valine or pantothenic acid synthesis, since these substances are required for growth (Law et al. 1976B Reiter and Oram 1962). In those microorganisms which can synthesize valine, this amino acid inhibits a-acetolactate synthesis (Rodopulo et al 1976). 

Snell, E. E., and Peterson, W. H., Growth factors for bacteria. X. Additional foctors required by certain lactic acid bacteria. /. Bacterial. 39, 273-285 (1940). 

Many names have been assigned to the lactic acid bacteria associated with brewing. It is probable however that most rod-shaped isolates may be classified as the heterofermentative species Lactobacillus brevis, the homo-fermentative species . casei and L, plantarum, and the homofermentative thermophilic species L. delbrueckii [14]. Cocci are also encountered, notably the homofermentative Pediococcus damnosus. (Less common because they are more sensitive to hop resins are P. pentosaceuslacidilactici. Streptococcus saprophyticus, S. epidermis and Micrococcus varians.) Micrococcus kristinae is however resistant to hop resins and low pH, but requires oxygen for growth [15]. An American report states that many breweries encounter L. brevis, L. plantarum and P. damnosus. When the primary fermentation is complete, Pediococcus continues to grow at the bottom of the fermenter in the deposited yeast [16]. 

Though the antibacterial effects of COS in the above experiments were lower than the chitosan, chitooligosaccharides have also shown the capability of inhibiting the growth of bacteria, including Salmonella Typhi, S. aureus, and lactic acid bacteria (Jeon et al., 2001). These researches further stated that the COS with molecular weight over 10,000Da is required for the effective antibacterial... 

Most of the vitamin Be in natural materials is present as phosphorylated derivatives of compounds I-III. Pyridoxal-5-phosphate (IV, Fig. i) was discovered in 1944 by Gale and Epps as an unidentified compound required for enzymatic decarboxylation of amino acids Gunsalus and co-workers subsequently showed it to be a phosphorylated pyridoxal -. Pyridoxamine-5-phosphate (V, Fig. i) was discovered by Rabinowitz and Snell by virtue of its differential activity in promoting growth of certain lactic acid bacteria. It is probable that pyridoxine-5-phosphate also occurs naturally, since it is both formed and oxidized to pyridoxal-5-phosphate by tissue enzymesi -. An unidentified conjugate of pyridoxine also occurs in cereal grains - . 

Successful cultivation of microorganisms for growth and identification requires use of various types of media, either liquid (referred to as hroths) or solid by inclusion of agar. For winemakers, a growth medium may he as simple as diluted sterile grape juice for the activation and expansion of yeast starter cultures or as complicated as that necessary to grow lactic acid bacteria. 

Amino acids and sometimes peptides supply lactic acid bacteria with their assimilable nitrogen. Amino acid requirements vary with respect to the species and even the strain. These acids can be strictly indispensable or simply growth activators. 

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